I recently purchased a Nitro Team 157. The waist width is 25cm, and I wear a size 10 boot. My toe overhang is about 7/8'' and my heel overhang is about 3/4''. I have Burton Custom bindings, and my boots sit relatively high off the board. My stance is ducked at 6 & 15 degrees.

Should I consider shaving a bit off the toe and heel of my boots or am I ok?

You will be fine. I only see it as a possible issue if your bombing steeps and I would assume you would want or have a wide all mountain board for pow...if you find it to be a issue, try a set of those Palmer power link plates to give you some extra clearance.